Keyboards are made through a series of injection molding, electronic assembly, and printing processes that transform raw plastic pellets, metal sheets, and circuit boards into a finished input device. The exact steps differ depending on whether the keyboard uses mechanical switches or a membrane design, but both types share core manufacturing stages: molding the plastic housing, building the circuit layer, creating the key mechanisms, printing legends onto keycaps, and assembling everything into a final unit.
Molding the Case
The outer shell of nearly every keyboard starts as plastic pellets, usually ABS or polycarbonate. These pellets are fed into an injection molding machine, heated past their melting point, and forced under high pressure into a multi-section mold shaped to the exact dimensions of the keyboard case. The mold can have two, three, or four interlocking sections to create complex shapes like the recessed slots where each key sits. Once injected, the molten plastic is cooled inside the mold, sometimes by circulating chilled water or a glycol mixture through channels in the mold walls to speed up solidification.
One challenge specific to keyboard cases is weld lines. Because the case has dozens of thin ribs between key openings, the two streams of molten plastic flowing around each opening meet and fuse imperfectly. Manufacturers manage this through mold design and material selection, but it’s an inherent constraint of injection molding that keyboard factories have to account for. Premium keyboards sometimes use aluminum or steel cases instead, which are CNC-machined from solid metal rather than molded.
Building the Circuit Board
Underneath the keys sits a printed circuit board (PCB), which is the electronic backbone that detects every keystroke. PCBs are manufactured separately from the case. Thin layers of fiberglass are laminated together and etched with copper traces that form the electrical pathways connecting each key position to a central microcontroller. Surface-mount components like the controller chip, diodes, and resistors are placed onto the board by automated pick-and-place machines, then soldered in place using reflow ovens that melt solder paste at precise temperatures.
After soldering, boards typically go through automated optical inspection, where cameras scan every solder joint to catch defects like bridges or cold joints. Some facilities also use X-ray inspection for components where the solder connections are hidden underneath the part. Through-hole components, if any remain in the design, are sometimes still placed and soldered by hand on less automated production lines.
How Mechanical Switches Are Made
Mechanical switches are miniature assemblies with five or more individual parts, and they go through their own dedicated production line before ever reaching a keyboard factory. Each switch contains a bottom housing, a top housing, a stem (the moving piece you press), a spring, and two metal contact leaves.
The plastic parts (housings and stems) are injection molded from materials like POM, nylon, or polycarbonate, each chosen for specific friction and sound properties. While those are being molded and inspected, the metal contact leaves go through a parallel process. Small and large leaves are stamped out of continuous metal bands, inserted into the bottom housing by robotic arms, and bent into the correct shape so they’ll make electrical contact when the stem pushes them together.
Final switch assembly happens on a single automated line. Bottom housings are fed through a circular sorting mechanism that orients each one correctly on a conveyor. The metal leaves are stamped and inserted first, then springs and stems are dropped in (sorted through similar circular organizers), and a small amount of lubricant is applied. The order of springs, stems, and lubing varies by factory. Finally, the top housing is pressed onto the bottom housing until the clips snap into place, producing a finished switch. The entire process is highly automated, with robotic arms handling each step in sequence.
How Membrane Layers Are Built
Membrane keyboards skip individual switches entirely. Instead, they use a three-layer sandwich: a top membrane sheet, a middle spacer layer with holes at each key position, and a bottom membrane sheet. Both membrane sheets have conductive traces printed on their inner faces, typically using silver or carbon ink applied through screen printing. When you press a key, a rubber dome collapses, pushing the top membrane through the spacer hole until it touches the bottom membrane. The two conductive traces meet, completing a circuit that registers the keystroke.
This design is far simpler and cheaper to produce than mechanical switches, which is why membrane keyboards dominate the budget market. The tradeoff is durability: membrane keyboards are typically rated for around 5 million keystrokes per key, compared to 50 to 100 million for mechanical switches. Some premium mechanical switches from brands like Cherry MX and Topre are rated for 100 million or more.
Printing Legends on Keycaps
The letters, numbers, and symbols on keycaps are applied through one of several processes, and the method chosen has a major impact on how long those legends last.
- Double-shot molding is the most durable approach. Each keycap is made from two separate plastic injections: one colored plastic forms the legend, and a second plastic fills in the rest of the cap around it. Because the legend is physically part of the keycap’s structure rather than printed on top, it can never wear off or fade. The tradeoff is cost, since every unique key requires its own dedicated mold. Double-shot also produces the sharpest legend edges, since the lines come from precision tooling rather than a printing process.
- Dye-sublimation uses heat to transfer dye from a printed sheet into the surface of the keycap plastic, penetrating a few microns deep. The legends are embedded in the material rather than sitting on top, so they resist wear for years of heavy use, though they can eventually fade. One limitation: the dye can only add color darker than the keycap itself. If you want light-colored legends on a dark cap, the entire cap has to be dyed around the legend (called reverse dye-sublimation), which is significantly more expensive. Dye-sub legends are also slightly less crisp than double-shot and can sometimes be felt as a subtle texture on the cap surface.
- Pad printing and laser etching are cheaper methods used on budget keyboards. Pad printing applies ink directly to the keycap surface, where it sits as a thin layer that wears away with use. Laser etching burns or marks the legend into the plastic, sometimes filled with paint afterward.
The Mounting Plate
Most keyboards include a rigid plate between the keycaps and the PCB. Switches clip or seat into this plate, which gives the keyboard structural rigidity and affects how each keystroke feels and sounds. Aluminum is the most common plate material, offering a moderately stiff feel and a clean, slightly bright sound. Brass plates are stiffer and produce a louder, more resonant metallic tone. Steel is very stiff and heavy with a loud, crisp sound profile. Some budget keyboards use polycarbonate or FR4 (fiberglass) plates, which flex more and produce a deeper, quieter sound.
Final Assembly
Once all the individual components are ready, final assembly brings them together. For mechanical keyboards, switches are inserted into the mounting plate (either soldered to the PCB or snapped into hot-swap sockets that allow removal without soldering). The plate-and-PCB assembly is fitted into the bottom case, stabilizers are installed under larger keys like the spacebar and shift keys, and foam or silicone dampening layers may be added between the PCB and case to reduce hollow sound. A USB connector or wireless module is attached, and the top case is screwed or clipped into place. Keycaps are pressed onto the switch stems last.
In high-volume factories, much of this is automated, with pick-and-place machines handling component placement and robotic arms doing repetitive assembly tasks. But manual labor remains common for certain steps: inspecting assembled boards, placing through-hole components, testing finished units, and handling the final packaging. Smaller production runs and custom keyboards rely even more heavily on hand assembly, with workers placing switches, testing each key, and tuning stabilizers individually.
Keycap Materials and Feel
The two most common keycap plastics are ABS and PBT, and they feel noticeably different. ABS is lighter, smoother, and cheaper to mold, but it develops a shiny, greasy texture over months of use as oils from your fingers polish the surface. PBT is denser, has a slightly grainy texture, and resists shine far longer. Less common materials include POM (very smooth and self-lubricating), polycarbonate (sometimes used for translucent keycaps that let RGB lighting shine through), resin, and even metal for specialty caps.